1. Field of the Invention
The present invention relates to an apparatus for manufacturing semiconductor devices and, more particularly, to a wafer sawing apparatus for separating a wafer into individual semiconductor chips.
2. Description of the Related Arts
After a well-known wafer fabrication process is performed a semiconductor wafer is cut and separated into individual semiconductor chips by a wafer sawing apparatus. The wafer sawing apparatus mostly uses a scribing blade as a cutter. Alternatively, a laser cutter may be used. The scribing blade rotates at high speed, and scribes the wafer along scribe lines. Therefore, the wafer is divided into a plurality of separate individual dices.
FIG. 1 is a plan view showing a conventional wafer sawing apparatus. FIG. 2 is a front view showing the conventional wafer sawing apparatus.
Referring to FIG. 1 and FIG. 2, a conventional wafer sawing apparatus 300 has a chuck table, on which a wafer 10 is fixedly mounted, and a scribing blade 321 which cuts the wafer 10 along scribe lines 13 in order to divide the wafer 10 into chips 11. The wafer sawing apparatus 200 further has a loader 330 in which a wafer cassette 20 containing the wafers 10 is placed, and transporters 340 and 350, which transfer the wafer 10 between the chuck table 311 and the wafer cassette 20.
As discussed, the wafer sawing apparatus 300 includes the first transporter 340 which puts the wafer 10 into the wafer cassette 20 or takes the wafer 10 out of the wafer cassette 20, and the second transporter 350 which rotates the wafer 10 at a predetermined angle and transfers the wafer 10 to the chuck table 311.
During the wafer sawing processing, the wafer 10 is being supported to a wafer ring 17 by an adhesive tape 15, which is attached to the backside of both the wafer 10 and the ring 17.
In the conventional wafer sawing apparatus 300, the first transporter 340 takes out the wafer 10 from the wafer cassette 20 placed on the loader 330, then the second transporter 350 transfers the wafer 10 to the chuck table 311. At this time, the second transporter 350 horizontally rotates the wafer 10.
Additionally, the first and second transporters 340, 350 have vacuum suction holes to affix the wafer 10 by vacuum suction force. The wafer 10 is stuck to the chuck table 311 by vacuum suction force. After affixing the wafer 10 to the chuck table 311, the scribing blade 321 cuts the wafer 10 along scribe lines so that the wafer 10 is separated into individual semiconductor chips 11.
The scribing blade 321 is rotated by a driving motor 323 and moved either in a direction of the y-axis by a y-axis driver 317 or in a direction of the z-axis by a z-axis driver 319. On the other hand, the chuck table 311 is moved in a direction of the x-axis by an x-axis driver 315. Herein, while the x-axis and the y-axis run are parallel to the ground, the z-axis runs perpendicular to the ground. In addition, the x-axis is perpendicular to the y-axis.
During scribing, silicon particles are produced as the scribing blade 321 abrades a surface of the wafer 10. These silicon particles may remain on the wafer 10 and cause defects in subsequent manufacturing processes. Therefore, the wafer sawing apparatus 300 has a spray nozzle 325 positioned on a side of the scribing blade 321 to spray a washing solution onto the scribing blade 321 and a top surface of the wafer 10. However, a cleaning operation by the washing solution still has limitations in effectively cleaning the wafer.
One of the approaches designed to overcome the limitations of using washing solution alone is disclosed in Japanese laid-open patent application No. 4-348546. The wafer sawing apparatus presented there is illustrated in FIG. 3. As shown in FIG. 3, the wafer sawing apparatus 400 has a revolving chuck table 411 on which a wafer 10 is mounted and to which a cylinder 417 is connected by a revolving unit 415. To effectively remove silicon particles, the cylinder 417 takes up the revolving chuck table 411 and thus the wafer 10 is positioned vertically. The scribing blade 421 is maneuverable along the x, y, and z axes, thereby controlling the sawing depth of the wafer 10. While the x-axis and the y-axis are parallel to the ground, the z-axis is perpendicular to the ground. In addition, the x-axis is perpendicular to the y-axis.
The conventional wafer sawing apparatus, including the wafer sawing apparatus shown in FIG. 3, has a drawback in that the chuck table occupies a relatively greater space since the chuck table lies horizontally. Therefore, the entire size of the wafer sawing apparatus becomes larger. Such a drawback becomes more serious if the wafer increases in size. For example, in the case of using 200-mm-diameter wafers (namely, 8-inch wafers), the wafer sawing apparatus covers an area of about 1.58 square meters (1.35 mxe2x80x2 1.17 m). In case of 300-mm-diameter wafers (namely, 12-inch wafers), the area of the wafer sawing apparatus increases about 2.55 square meters (1.82 m xe2x80x2 1.4 m).
Consequently, there is a need for a wafer sawing apparatus that occupies a smaller space and removes contaminants such as silicon scraps and dust more efficiently.
A wafer sawing apparatus that has a smaller xe2x80x9cfootprintxe2x80x9d than those of the prior art is provided. Also, a wafer sawing apparatus that can effectively remove silicon scraps and dust produced during the sawing process is provided.
In accordance with the preferred embodiment of the present invention, the wafer sawing apparatus comprises a vertical chuck table, which has a first surface to hold a wafer and a second surface connected to a driving member. The first and second surfaces of the chuck table are disposed substantially vertically to a support surface for the chuck table. The wafer sawing apparatus further includes a scribing member that moves perpendicular to the front surface of the wafer or the chuck table and separates the wafer into individual semiconductor chips. The apparatus further provides transporting members that transfer the wafer, and the wafer is then fixedly supported relative to the chuck table by the transporting members in an upright position.
The vertical chuck table or the scribing member is movable along the x, y or z-axis. Here, the direction of x-axis runs perpendicular to the wafer stage and parallel to the ground or the support surface for the chuck table, direction of y-axis runs parallel to the wafer stage and parallel to the ground, and direction of z-axis runs parallel to the wafer stage and perpendicular to the ground. Additionally, the scribing member may comprise one or more laser cutters or one or more scribing blades rotated by a driving motor, so that the scribing blade runs parallel to the ground or vertical to the ground.
As a result, the set-up dimensions of the apparatus can be decreased even as wafer size increases. Further, contaminants such as silicon scraps and dust on the wafer can be efficiently removed during the wafer sawing process.